Oxydecahydronaphthalene modulators of HM74

ABSTRACT

Host cells expressing HM74 were used to obtain oxydecalin-like molecules with agonist activity having the following structure:

BACKGROUND OF THE INVENTION

The G protein-coupled receptors (GPCRs) are integral membrane proteinsthat are involved in cellular signal transduction. GPCRs respond to avariety of extracellular signals, including neurotransmitters, hormones,odorants and light, and are capable of transducing signals so as toinitiate a second messenger response within the cell. Many therapeuticdrugs target GPCRs because those receptors mediate a wide variety ofphysiological responses, including inflammation, vasodilation, heartrate, bronchodilation, endocrine secretion and peristalsis.

Diseases such as asthma, chronic obstructive pulmonary disease (COPD),psoriasis, and rheumatoid arthritis (RA) generally are considered tohave an inflammatory etiology involving T helper cells,monocyte-macrophages and eosinophils. Current anti-inflammatory therapywith corticosteroids is effective in asthma but is associated withmetabolic and endocrine side effects. The same is possibly true forinhaled formulations that can be absorbed through lung or nasal mucosa.Satisfactory oral therapies for RA or COPD currently are lacking.

Molecular cloning of HM74 from human monocytes predicted HM74 to be achemokine receptor (Nomura et al., Int. Immunol. (1993)5(10):1239-1249). HM74 is expressed primarily in bone marrow, spleen,tonsil and trachea.

Human cells also contain a related but distinct receptor, HM74A. Theamino acid sequences of HM74 and HM74A are about 95% identical. However,the ligand of HM74A is known whereas the ligand of HM74 is unknown.Niacin or nicotinic acid is the HM74A ligand, Wise et al., J. Biol.Chem. 278:9869-9874, 2003. Niacin is but a poor activator of HM74.

The mouse genome contains an HM74A gene but not an HM74 gene.

Under certain circumstances, HM74 and HM74A demonstrate coregulation.Using Taqman-PCR, applicants found that HM74 and HM74A expression isinduced 50-fold by TNFα in granulocytes and 10-20-fold by LPS or TNFα inmonocytes. HM74 and HM74 expression also are induced 4-5-fold in normalhuman bronchial epithelial cells with the TH2 cytokines, IL-4 or IL-13,known to be important in the etiology of asthma. HM74 and HM74Aexpression are upregulated in human primary eosinophils by IL-5.Finally, pulmonary HM74A expression is upregulated in a murineexperimental asthma model.

The restricted tissue distribution of HM74 and HM74A, and the regulationthereof suggest a role for HM74 and HM74A in inflammatory processes,such as asthma, COPD and RA.

Given the role GPCRs have in disease and the ability to treat diseasesby modulating the activity of GPCRs, identification and characterizationof GPCR ligands can provide for the development of new compositions andmethods for treating disease states that involve the activity of a GPCR.The instant invention identifies and characterizes molecules that engageHM74, and provides compositions and methods for applying the discoveryto the identification and treatment of related diseases.

SUMMARY OF THE INVENTION

The instant invention relates to molecules that activate HM74 but notHM74A.

In another aspect of the invention, methods are disclosed foridentifying modulators of HM74. For example, a method of interestcomprises the steps of providing a chemical moiety, providing a cellexpressing HM74 and determining whether the chemical moiety modulatesthe signaling activity of HM74, including whether such modulation occursin the presence or absence of an agonist of the instant invention. In arelated aspect, the chemical moieties can include, but are not limitedto, peptides, antibodies, agonists, inverse agonists and antagonists.Alternatively, a known modulator can be used in a competition assay toidentify other modulators.

Fused ring dihydropyrans (also known as oxydecahydronaphthalene andoxydecalin) activate HM74. Those compounds cause selectivedose-responsive calcium mobilization in cells expressing HM74, such asCHO cells, 293 cells and L1.2 cells.

The oxydecalins of interest have the following structure:

where X is O, NR₂ or S;

R₁ is a C₁-C₁₈ alkyl, which may be branched, may contain a heteroatom ormay be substituted, or combinations thereof; a C₁-C₁₈ alkenyl, which maybe branched, may contain a heteroatom or may be substituted, orcombinations thereof; a C₁-C₁₈ alkynl, which may be branched, maycontain a heteroatom or may be substituted, or combinations thereof; aC₃-C₁₈ aryl which may contain a side group, may contain a bridge, maycontain a heteroatom or may be substituted, or combinations thereof; ora C₅-C₁₈ cycloalkyl which may contain a side group, may contain abridge, may contain a heteroatom or may be substituted, or combinationsthereof; or combinations thereof;

R2 is an R1 group; or R2 can be a (C1-C10) alkyl-(C3-C10) cycloalkyl,which may be branched, may contain a heteroatom or may be substituted,or combinations thereof; or X and R2 may form a ring;

R3 is H or R1; and

Y is carbonyl, a Schiff base, an oxine, a ketal, an acetal, anoxazolidine, a thiazolidine or an enol ester.

The compounds of interest generally are agonists. Thus, a compound ofinterest could be developed as a drug candidate. A compound of interestalso could be used to identify other molecules that modulate HM74 by,for example, competition assays.

Another aspect of the invention includes therapeutic compositions, wheresuch compositions include nucleic acids, antibodies, polypeptides,agonists, inverse agonists and antagonists. Further, methods of theinvention also include methods of treating disease states and modulatingHM74 signaling activity by administering such therapeutic compositionsto a patient in need thereof.

Those and other aspects of the invention will become evident onreference to the following detailed description and attached drawings.In addition, various references are set forth below that describe inmore detail certain procedures or compositions. Each of the referenceshereby is incorporated herein by reference as if each were individuallynoted for incorporation.

DETAILED DESCRIPTION OF THE INVENTION

The instant invention is based on the discovery of molecules thatactivate HM74.

The HM74 coding sequence is known, Nomura et al., supra. Methods forobtaining, making and using HM74 are provided herein. Changes to theHM74 coding sequence and amino acid are tolerated so long as the knownfunctional activities of HM74 are not impacted adversely.

The instant compounds modulate HM74, are agonists of HM74, and thus aredrug candidates for disorders characterized by inflammation, such asasthma.

The instant compounds also can be used to screen for HM74 antagonists.For example, cells expressing HM74 are exposed to a test compound andthen to an agonist of the instant invention. Then the effect of the testcompound on, for example, calcium mobilization, can be ascertained todetermine whether the test compound reduces the calcium mobilizationlevels induced by the agonist of the instant invention.

Other such assays to identify, for example, agonists and inverseagonists, are contemplated to fall within the scope of the instantinvention.

The oxydecalins of interest have the following structure:

where X is O, NR₂ or S;

R₁ is a C₁-C₁₈ alkyl, which may be branched, may contain a heteroatom ormay be substituted, or combinations thereof; a C₁-C₁₈ alkenyl, which maybe branched, may contain a heteroatom or may be substituted, orcombinations thereof; a C₁-C₁₈ alkynl, which may be branched, maycontain a heteroatom or may be substituted, or combinations thereof; aC₃-C₁₈ aryl which may contain a side group, may contain a bridge, maycontain a heteroatom or may be substituted, or combinations thereof; ora C₅-C₁₈ cycloalkyl which may contain a side group, may contain abridge, may contain a heteroatom or may be substituted, or combinationsthereof; or combinations thereof;

R₂ is an R₁ group; or R₂ can be a (C₁-C₁₀) alkyl-(C₃-C₁₀) cycloalkyl,which may be branched, may contain a heteroatom or may be substituted,or combinations thereof; or X and R₂ may form a ring;

R₃ is H or R₁; and

Y is carbonyl, a Schiff base, an oxine, a ketal, an acetal, anoxazolidine, a thiazolidine or an enol ester.

The compounds of interest generally are agonists. Thus, a compound ofinterest could be developed as a drug candidate. A compound of interestalso could be used to identify other molecules that modulate HM74 by,for example, competition assays.

The term “alkyl” means a straight or branched chain hydrocarbon.Representative examples are methyl, ethyl, propyl, isopropyl, butyl,isobutyl, tert-butyl, sec-butyl, pentyl and hexyl. The hydrocarbon cancontain one or more unsaturated triple bonds.

The term “alkoxy” means an alkyl group bound to an oxygen atom. Examplesare methoxy, ethoxy, propoxy, butoxy and pentoxy.

“Aryl” is a ring which is an aromatic hydrocarbon. Examples includephenyl and naphthyl.

“Heteroatom” generally is an atom that differs from those that typify amolecule. Thus, in a hydrocarbon, any atom not a carbon or a hydrogen isa heteroatom. Common biologically acceptable heteroatoms include oxygen,sulfur and nitrogen.

The term “heteroaryl” relates to an aryl group where one or more carbonatoms is replaced with a heteroatom. Examples are pyridyl, imidazolyl,pyrrolyl, thienyl, furyl, pyranyl, pyrimidinyl, pyridazinyl, indolyl,quinolyl, naphthyridinyl and isoxazoyl.

“Branched” means the structure contains one or more branches at one ormore sites. A branch can be an R group as defined above or other sidegroup.

The term “cycloalkyl” refers to a cyclic hydrocarbon. Some examples arecyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl. May contain abridge of varying length.

“Heterocycle” is a cycloalkyl where one or more carbon atoms arereplaced with a heteroatom. Examples are pyrrolidinyl, piperidinyl andpiperazinyl.

The term “heteroalkyl” is an alkyl where one or more carbon atoms arereplaced with a heteroatom. An ether is a heteroalkyl.

By “substituted” is meant that the base organic radical has one or moresubstituent groups. Thus, an atom or group replaces another atom orgroup in a molecule. Representative substituents include a halogen,C1-C8 alkyl, —CN, alkoxyl, hydroxyl, sulfide, sulfate, sulfonamide,amine, amide, an alcohol, a keto group, C6-C18 aryl, a halogenatedC1-C18 alkyl, a nitrite group or a nitrate group.

A “halogen” is, for example, chlorine, fluorine or bromine.

An “alkenyl” is a hydrocarbon containing one or more carbon-carbondouble bonds. The hydrocarbon can be branched.

The term “ring” means one, one of a plurality of ring structures or aplurality of ring structures, where two or more of the plurality ofrings can be fused, wherein the or one or more of the plurality of ringsmay be aromatic, contain a heteroatom, may be substituted or acombination thereof. The ring may be bicyclic or polycyclic. The ringmay contain a bridge of varying length.

The term “side group” means an atom or molecule attached to anotherstructure. Thus, a side group can be an R group defined above, an alkyl,an aryl, a cycloalkyl and so on.

The term “bridge” refers to a linker between two structures. Forexample, a non-cyclic hydrocarbon, such as an alkyl, alkenyl and thelike, which can contain a heteroatom, can be substituted, can bebranched or combinations thereof, can connect two cyclic hydrocarbons,such as aryl or cycloalkyl groups. The bridge also may be containedwithin a cyclic structure joining at least two atoms of the cyclicstructure. The intramolecular bridge may contain 0, 1, 2, 3, 4 or moreatoms. The intramolelcular bridge may be linear, branched and containsubstitutions.

The compounds of interest contain functional groups that can bederivatized to form prodrugs to enhance bio-availability. Thus, theinstant invention contemplates variants of the active compounds ofinterest that following administration, are metabolized to a bioactiveform. Such bioactive drug precursors are also known as bioreversiblecarriers, latent drugs, drug delivery systems or prodrugs.(“Bioreversible Carriers in Drug Design” E. B. Roche, ed., Pergamon,N.Y., 1987; “Prodrugs as Novel Drug Delivery Systems”, Higuchi & Stella,eds., American Chemical Society, DC, 1975)

Chemical modification of drugs is directed to address particular aspectsof pharmacodynamics, such as how to enhance availability of a polarcompound that must cross a lipid barrier, how to stabilize a compoundnormally susceptible to degradation in vivo and so on.

Other reasons to make prodrugs include bioactive drug toxicity, lack ofspecificity, instability, being metabolized at the absorption site,being absorbed too quickly, patient compliance, such as poor taste orpain at injection site, poor doctor acceptance or formulation problemsas well.

A common modification is esterification, which is not limited toderivation of a carboxyl group. Chemistry exists for making suchderivatives, for example, for amines, imines, sulfur containingsubstituents and amides as well.

In the case of esters, various substituents can be added thereto,including unbranched, cyclic or branched hydrocarbons that can besubstituted, can contain one or more double or triple bonds, can containring structures, the hydrocarbon backbone can contain one or moreheteroatoms, such as nitrogen, sulfur or oxygen, and so on.

When considering the R group for constructing the ester, another factorto consider is the susceptibility of enzymic cleavage. Thus, stericcharge and conformational factors can be determinative forbioavailability. For example, a branched alkyl group may provide sterichindrance for accessibility to the esterase active site, thereby slowingthe rate of hydrolysis. That either may be less desirable,bioavailability is delayed, or desirable, bioavailability is prolonged.

In other circumstances, it is desirable to enhance aqueous solubility ofa drug. Examples of substituents that achieve that goal includesuccinates, sulfates, hemisuccinates, phosphates, amino acids, acetates,amines and the like.

Nitrogens of amides, imides, carbonates, hydrantoins and the like can bederivatized. Suitable groups for reaction to the nitrogen includehydroxymethyl groups, or hydroxyalkyl groups in general, acyloxyalkylgroups and acyl groups.

Carbonyl groups also are sites for derivation. Examples of derivativesare Schiff bases, oxines, ketals, acetals, oxazolidines, thiazolidinesand enol esters.

While the derivatives discussed above comprise covalent bonding of thesubstituent to the drug, a substituent may be attached to the drug inother ways, for example, hydrogen bonding, van der Waals forces,electrostatic forces, hydrophobic interactions and the like.

Yet another means of derivatization is to use substituents that areremoved from a prodrug by a nonenzymatic mechanism. Examples includeprodrugs that contain (2-oxo-1,3-dioxol-4-yl) methyl esters, Mannichbases, oxazolidines, esters with a basic side chain that catalyzeintramolecular hydrolysis and esters or amides that undergo anintramolecular nucleophilic cyclization-elimination reaction. Thecyclization mechanism is available for drugs containing phenols,alcohols and amines. “Prodrug Design” Testa & Mayer in “Encyclopedia ofPharmaceutical Technology,” 2nd ed. V. 3, Swarbrick & Boylan, eds.,Marcel Dekker, 2002.

Therefore, the instant invention contemplates any further modificationof the compounds of interest practicing known synthesis methods toobtain compounds that once administered react or are acted on in vivo toyield a compound that modulates HM74 activity.

The term “equivalent amino acid residues” herein means the amino acidsoccupy substantially the same position within a protein sequence whentwo or more sequences are aligned for analysis. Preferred HM74polypeptides of the instant invention have an amino acid sequencesufficiently identical to that of the wild-type HM74. By “wild-type” ismeant the most prevalent form or allele present in a defined population,whether local or wider in scope. The term “sufficiently identical” isused herein to refer to a first amino acid or nucleotide sequence thatcontains a sufficient or minimum number of identical or equivalent(e.g., with a similar side chain) amino acid residues or nucleotides toa second amino acid or nucleotide sequence such that the first andsecond amino acid or nucleotide sequences have a common structuraldomain and/or common functional activity. For example, amino acid ornucleotide sequences that contain a common structural domain having atleast 96% identity with an HM74 activity are defined herein assufficiently identical.

As used interchangeably herein, an “HM74 activity”, “biological activityof HM74” or “functional activity of HM74”, refers to an activity exertedby an HM74 protein, polypeptide or nucleic acid molecule on an HM74expressing cell as determined in vivo or in vitro, according to standardtechniques. An HM74 activity can be a direct activity, such as anassociation with or an enzymatic activity on a second protein or anindirect activity, such as a cellular signaling activity mediated byinteraction of the HM74 with a second protein. In a preferredembodiment, an HM74 activity includes at least one or more of thefollowing activities: (i) the ability to interact with proteins in theHM74 signaling pathway; (ii) the ability to interact with an HM74ligand; (iii) the ability to alter the host cell when activated; (iv)activation on binding a molecule of the invention; and (v) the abilityto interact with an intracellular target protein.

One aspect of the invention pertains to expressing HM74 in cells thatdemonstrate a response when HM74 is activated. As used herein, the term“nucleic acid molecule” is intended to include DNA molecules (e.g., cDNAor genomic DNA) and RNA molecules (e.g., mRNA) and analogs of DNA or RNAgenerated using nucleotide analogs. The nucleic acid molecule can besingle-stranded or double-stranded, but preferably is double-strandedDNA.

An “isolated” nucleic acid molecule is one that is separated from othernucleic acid molecules present in the natural source of the nucleicacid. Preferably, an “isolated” nucleic acid is free of sequences thatnaturally flank the nucleic acid encoding HM74 (i.e., sequences locatedat the 5′ and 3′ ends of the nucleic acid) in the genomic DNA of theorganism from that the nucleic acid is derived. The isolated HM74nucleic acid molecule can contain less than about 5 kb, 4 kb, 3 kb, 2kb, 1 kb, 0.5 kb or 0.1 kb of nucleotide sequences that naturally flankthe open reading frame nucleic acid molecule in genomic DNA of the cellfrom which the nucleic acid is derived. Moreover, an “isolated” nucleicacid molecule, such as a cDNA molecule, can be substantially free ofother cellular material or culture medium when produced by recombinanttechniques or substantially free of chemical precursors or otherchemicals when synthesized chemically.

A nucleic acid molecule of the instant invention, e.g., a nucleic acidmolecule encoding HM74 can be isolated using standard molecular biologytechniques and the sequence (Nomura et al., supra). Using all or aportion of the HM74 sequence, HM74 nucleic acid molecules can beisolated using standard hybridization and cloning techniques (e.g., asdescribed in Sambrook et al., eds., Molecular Cloning: A LaboratoryManual, 2nd ed., Cold Spring Harbor Laboratory Press, Cold SpringHarbor, N.Y., 1989).

A nucleic acid molecule of the invention can be amplified using cDNA,mRNA or genomic DNA as a template and appropriate oligonucleotideprimers according to standard PCR amplification techniques. The nucleicacid so amplified can be cloned into an appropriate vector andcharacterized by DNA sequence analysis. Furthermore, oligonucleotidescorresponding to HM74 nucleotide sequences can be prepared by standardsynthetic techniques, e.g., using an automated DNA synthesizer.

Moreover, the nucleic acid molecule of the invention can comprise onlyportions of a nucleic acid sequence encoding HM74, for example, afragment that encodes the extracellular domains and/or intracellulardomains that yield a detectable intracellular event, when a ligand isbound thereto. Preferably that detectable intracellular event is onethat is observed when HM74 is activated in a normal host cell.

A nucleic acid fragment encoding a “biologically active portion of HM74”can be prepared by isolating a portion of HM74 that encodes apolypeptide having an HM74 biological activity, expressing the encodedportion of HM74 protein (e.g., by recombinant expression in vitro) andassessing the activity of the encoded portion of HM74.

The invention further encompasses nucleic acid molecules that differfrom the nucleotide sequence of the disclosed HM74 due to degeneracy ofthe genetic code and thus encode substantially the same HM74 protein asthat previously disclosed.

It will be appreciated by those skilled in the art that DNA sequencepolymorphisms that lead to changes in the amino acid sequences of HM74may exist within a population (e.g., the human population). Such geneticpolymorphism in the HM74 coding sequence may exist among individualswithin a population due to natural allelic variation. An allele is oneof a group of genes that occur alternatively at a given genetic locus.As used herein, the terms “gene” and “recombinant gene” refer to nucleicacid molecules comprising an open reading frame encoding an HM74protein, preferably a mammalian HM74 protein. As used herein, the phrase“allelic variant” refers to a nucleotide sequence that occurs at an HM74locus or to a polypeptide encoded by the nucleotide sequence.Alternative alleles can be identified by sequencing the gene of interestin a number of different individuals. That can be carried out readily byusing hybridization probes to identify the same genetic locus in avariety of individuals. Any and all such nucleotide variations andresulting amino acid polymorphisms or variations in HM74 that are theresult of natural allelic variation and that do not alter the functionalactivity of HM74 are intended to be within the scope of the invention.

Moreover, nucleic acid molecules encoding HM74 proteins from otherspecies (HM74 homologues) with a nucleotide sequence that differs fromthat of a human HM74 but have substantially the same activity, areintended to be within the scope of the invention. Nucleic acid moleculescorresponding to natural allelic variants and homologues of the HM74cDNA of the invention can be isolated based on identity with the humanHM74 nucleic acids disclosed herein using the human cDNA or a portionthereof, as a hybridization probe according to standard hybridizationtechniques under stringent hybridization conditions.

As used herein, the term “hybridizes under stringent conditions” isintended to describe conditions for hybridization and washing underwhich nucleotide sequences typically remain hybridized. Such stringentconditions are known to those skilled in the art and can be found in“Current Protocols in Molecular Biology”, John Wiley & Sons, N.Y.(1989), 6.3.1-6.3.6. A preferred, non-limiting example of stringenthybridization conditions are hybridization in 6×sodium chloride/sodiumcitrate (SSC) at about 45° C., followed by one or more washes in0.2×SSC, 0.1% SDS at 50-65° C. Preferably, an isolated nucleic acidmolecule of the invention that hybridizes under stringent conditions tothe sequence HM74 or the complement thereof corresponds to anaturally-occurring nucleic acid molecule. As used herein, a“naturally-occurring” nucleic acid molecule refers to an RNA or DNAmolecule having a nucleotide sequence that occurs in nature (e.g.,encodes a natural protein).

In addition to naturally-occurring allelic variants of the HM74 sequencethat may exist in the population, the skilled artisan will furtherappreciate that changes can be introduced by mutation into thenucleotide sequence, thereby leading to changes in the amino acidsequence of the encoded HM74, without substantially altering thebiological activity of the HM74 protein. Thus, one can make nucleotidesubstitutions leading to amino acid substitutions at “non-essential”amino acid residues. A “non-essential” amino acid residue is a residuethat can be altered from the wild type sequence of HM74 withoutsubstantially altering the biological activity. An “essential” aminoacid residue is one required for substantial biological activity. Forexample, amino acid residues that are not conserved or onlysemi-conserved among HM74 of various species may be non-essential foractivity and thus would be likely targets of alteration. Alternatively,amino acid residues that are conserved among the HM74 proteins ofvarious species may be essential for activity and thus would not belikely targets for alteration.

Accordingly, another aspect of the invention pertains to nucleic acidmolecules encoding HM74 proteins that contain changes in amino acidresidues that are not essential for activity. Such HM74 proteins differfrom the known amino acid sequence yet retain biological activity. Inone embodiment, the isolated nucleic acid molecule includes a nucleotidesequence encoding a protein that includes an amino acid sequence that isat least 96%, 97%, 98%, 99% or 100% identical to the known HM74 aminoacid sequence.

An isolated nucleic acid molecule encoding an HM74 protein having asequence that differs from that of the known HM74 can be created byintroducing one or more nucleotide substitutions, additions or deletionsinto the nucleotide sequence of the known HM74 such that one or moreamino acid substitutions, additions or deletions are introduced into theencoded protein.

Mutations can be introduced by standard techniques, such assite-directed mutagenesis and PCR-mediated mutagenesis. Preferably,conservative amino acid substitutions are made at one or more predictednon-essential amino acid residues. A “conservative amino acidsubstitution” is one in which the amino acid residue is replaced with anamino acid residue having a similar side chain. Families of amino acidresidues having similar side chains are defined in the art. The familiesinclude amino acids with basic side chains (e.g., lysine, arginine andhistidine), acidic side chains (e.g., aspartic acid and glutamic acid),uncharged polar side chains (e.g., glycine, asparagine, glutamine,serine, threonine, tyrosine and cysteine), nonpolar side chains (e.g.,alanine, valine, leucine, isoleucine, proline, phenylalanine, methionineand tryptophan), beta-branched side chains (e.g., threonine, valine andisoleucine) and aromatic side chains (e.g., tyrosine, phenylalanine,tryptophan and histidine). Thus, a predicted nonessential amino acidresidue in HM74 preferably is replaced with another amino acid residuefrom the same side chain family. Alternatively, mutations can beintroduced randomly along all or part of an HM74 coding sequence, suchas by saturation mutagenesis, and the resultant mutants can be screenedfor HM74 biological activity to identify mutants that retain activity.Following mutagenesis, the encoded protein can be expressedrecombinantly and the activity of the protein can be determined.

Examples of modified nucleotides that can be used to generate nucleicacids of interest include 5-fluorouracil, 5-bromouracil, 5-chlorouracil,5-iodouracil, hypoxanthine, xanthine, 4-acetylcytosine,5-(carboxyhydroxylmethyl)uracil,5-carboxymethylaminomethyl-2-thiouridine,5-carboxymethylaminomethyluracil, dihydrouracil, β-D-galactosylqueosine,inosine, N6-isopentenyladenine, 1-methylguanine, 1-methylinosine,2,2-dimethylguanine, 2-methyladenine, 2-methylguanine, 3-methylcytosine,5-methylcytosine, N6-adenine, 7-methylguanine,5-methylaminomethyluracil, 5-methoxyaminomethyl-2-thiouracil,

β-D-mannosylqueosine, 5-methoxycarboxymethyluracil, 5-methoxyuracil,2-methylthio-N6-isopentenyladenine, uracil-5-oxyacetic acid,wybutoxosine, pseudouracil, queosine, 2-thiocytosine,5-methyl-2-thiouracil, 2-thiouracil, 4-thiouracil, 5-methyluracil,uracil-5-oxyacetic acid methylester, uracil-5-oxyacetic acid,5-methyl-2-thiouracil, 3-(3-amino-3-N-2-carboxypropyl)uracil and2,6-diaminopurine.

One way to impact HM74 function is to affect HM74 expression. Thus,transcription levels can be manipulated for lesser or greater levels ofHM74 mRNA, which would in turn lead to lesser or greater levels of HM74expression at the cell surface. One way to achieve such manipulation isby using regulatable promoters which can be introduced at theappropriate site in the genome, in proximity of the HM74 coding sequenceby, for example, homologous recombination.

Accordingly, another aspect of the invention pertains to anti-HM74antibodies. The term “antibody” as used herein refers to immunoglobulinmolecules and immunologically active portions of immunoglobulinmolecules, i.e., molecules that contain an antigen-binding site thatspecifically binds an antigen, such as HM74. A molecule thatspecifically binds to HM74 is a molecule that binds HM74, but does notsubstantially bind other molecules in a sample, e.g., a biologicalsample, that naturally contains HM74. Examples of immunologically activeportions of immunoglobulin molecules include F(ab) and F(ab′)2 fragmentsthat can be generated by treating the antibody with an enzyme such aspepsin. The invention provides polyclonal and monoclonal antibodies thatbind HM74. The term “monoclonal antibody” or “monoclonal antibodycomposition”, as used herein, refers to a population of antibodymolecules that contain only one species of an idiotype or a clone of anantigen-binding site capable of immunoreacting with a particular epitopeof HM74. A monoclonal antibody composition thus typically displays asingle binding affinity for a particular HM74 protein epitope.

Various other antigen-binding forms of antibodies can be made as knownin the art, including fragments, chimeric antibodies, recombinantantibodies, humanized antibodies and the like.

Another aspect of the invention pertains to vectors, preferablyexpression vectors, containing a nucleic acid encoding HM74 (or aportion thereof). As used herein, the term “vector” refers to a nucleicacid molecule capable of transporting another nucleic acid linkedthereto. One type of vector is a “plasmid” that refers to a circulardouble-stranded DNA loop into which additional DNA segments can beligated. Another type of vector is a viral vector, wherein additionalDNA segments can be ligated into a viral genome. Certain vectors arecapable of autonomous replication in a host cell (e.g., bacterialvectors having a bacterial origin of replication and episomal mammalianvectors). Other vectors (e.g., non-episomal mammalian vectors) areintegrated into the genome of a host cell on introduction into the hostcell and thereby are replicated along with the host genome. Moreover,certain vectors, expression vectors, are capable of directing theexpression of genes operably linked thereto. In general, expressionvectors of utility in recombinant DNA techniques are often in the formof plasmids (vectors). However, the invention is intended to includesuch other forms of expression vectors, such as viral vectors (e.g.,replication defective retroviruses, adenoviruses and adeno-associatedviruses), that serve equivalent functions.

The recombinant expression vectors of the invention comprise nucleicacid of the invention in a form suitable for expression of the nucleicacid in a host cell. That means the recombinant expression vectorsinclude one or more regulatory sequences, selected on the basis of thehost cells to be used for expression, which is linked operably to thenucleic acid to be expressed. Within a recombinant expression vector,“operably linked” is intended to mean that the nucleotide sequence ofinterest is linked to the regulatory sequence(s) in a manner that allowsfor expression of the nucleotide sequence (e.g., in an in vitrotranscription/translation system or in a host cell when the vector isintroduced into the host cell). The term “regulatory sequence” isintended to include promoters, enhancers and other expression controlelements (e.g., polyadenylation signals). Such regulatory sequences aredescribed, for example, in Goeddel, Gene Expression Technology: Methodsin Enzymology Vol. 185, Academic Press, San Diego, Calif. (1990).Regulatory sequences include those which direct constitutive expressionof the nucleotide sequence in many types of host cells (e.g., tissuespecific regulatory sequences). It will be appreciated by those skilledin the art that the design of the expression vector can depend on suchfactors as the choice of host cell to be transformed, the level ofexpression of protein desired etc. The expression vectors of theinvention can be introduced into host cells to produce proteins orpeptides encoded by nucleic acids as described herein (e.g., HM74,mutant forms of HM74, fusion proteins etc.).

The recombinant expression vectors of the invention can be designed forexpression of HM74 in prokaryotic or eukaryotic cells, e.g., bacterialcells such as E. coli, insect cells (using baculovirus expressionvectors), yeast cells or mammalian cells. Suitable host cells arediscussed further in Goeddel, supra. Alternatively, the recombinantexpression vector can be transcribed and translated in vitro, forexample using T7 promoter regulatory sequences and T7 polymerase.

In another embodiment, the HM74 expression vector is a yeast expressionvector. Examples of vectors for expression in yeast such as S.cerevisiae include pYepSecl (Baldari et al., EMBO J. (1987) 6:229-234),pMFa (Kurjan et al., Cell (1982) 30:933-943), pJRY88 (Schultz et al.,Gene (1987) 54:113-123), pYES2 (Invitrogen Corporation, San Diego,Calif.) and pPicZ (Invitrogen Corp, San Diego, Calif.).

Alternatively, HM74 can be expressed in insect cells using baculovirusexpression vectors. Baculovirus vectors available for expression ofproteins in cultured insect cells (e.g., Sf 9 cells) include the pAcseries (Smith et al., Mol. Cell. Biol. (1983) 3:2156-2165) and the pVLseries (Lucklow et al., Virology (1989) 170:31-39).

In yet another embodiment, a nucleic acid of the invention is expressedin mammalian cells using a mammalian expression vector. Examples ofmammalian expression vectors include pCDM8 (Seed, Nature (1987) 329:840)and pMT2PC (Kaufman et al., EMBO J. (1987) 6:187-195). When used inmammalian cells, the control functions of the expression vector oftenare provided by viral regulatory elements. For example, commonly usedpromoters are derived from polyoma, adenovirus 2, cytomegalovirus andsimian virus 40. For other suitable expression systems for bothprokaryotic and eukaryotic cells, see chapters 16 and 17 of Sambrook etal., supra.

For stable transformation of mammalian cells, it is known that,depending on the expression vector and transformation technique used,only a small fraction of cells may integrate the foreign DNA into thegenome. To identify and to select the integrants, a gene that encodes aselectable marker (e.g., for resistance to antibiotics) generally isintroduced into the host cells along with the gene of interest.Preferred selectable markers include those that confer resistance todrugs, such as G418, hygromycin and methotrexate. Nucleic acid encodinga selectable marker can be introduced into a host cell on the samevector as that encoding HM74 or can be introduced on a separate vector.Cells stably transfected with the introduced nucleic acid can beidentified by drug selection (e.g., cells that have incorporated theselectable marker gene will survive, while the other cells die).

The compounds of interest that engage and activate HM74 are fused ringdihydropyrans, which includes oxydecalin-like compounds. Oxydecalin isanother name for oxydecahydroraphthalene. Such dihydropyrans have thegeneral structure:

The dihydropyrans and oxydecalins of interest can be made as taught inU.S. Pat. No. 6,399,653, WO 97/48691 and in von Roedern, Mol. Div.(1998) 3:253-256.

The oxydecalins of interest have the following structure:

where X is O, NR₂ or S;

R₁ is a C₁-C₁₈ alkyl, which may be branched, may contain a heteroatom ormay be substituted, or combinations thereof; a C₁-C₁₈ alkenyl, which maybe branched, may contain a heteroatom or may be substituted, orcombinations thereof; a C₁-C₁₈ alkynl, which may be branched, maycontain a heteroatom or may be substituted, or combinations thereof; aC₃-C₁₈ aryl which may contain a side group, may contain a bridge, maycontain a heteroatom or may be substituted, or combinations thereof; ora C₅-C₁₈ cycloalkyl which may contain a side group, may contain abridge, may contain a heteroatom or may be substituted, or combinationsthereof; or combinations thereof;

R₂ is an R₁ group; or R₂ can be a (C₁-C₁₀) alkyl-(C₃-C₁₀) cycloalkyl,which may be branched, may contain a heteroatom or may be substituted,or combinations thereof; or X and R₂ may form a ring;

R₃ is H or R₁; and

Y is carbonyl, a Schiff base, an oxine, a ketal, an acetal, anoxazolidine, a thiazolidine or an enol ester.

The compounds of interest generally are agonists. Thus, a compound ofinterest could be developed as a drug candidate. A compound of interestalso could be used to identify other molecules that modulate HM74 by,for example, competition assays.

Preferred compounds are those where when R2 is methyl, ethyl orcyclohexyl, R1 is not an n-alkyl or a C1-C4 branched alkyl; or when R1is a C1-C4 alcohol or a C1-C4 branched alkyl which may be substitutedwith an acetyl group, R1 is not an n(-C1-C8) alkyl, a (C1-C4) branchedalkyl or a thio substituted phenyl.

The term “alkyl” means a straight or branched chain hydrocarbon.Representative examples are methyl, ethyl, propyl, isopropyl, butyl,isobutyl, tert-butyl, sec-butyl, pentyl and hexyl. The hydrocarbon cancontain one or more unsaturated triple bonds.

The term “alkoxy” means an alkyl group bound to an oxygen atom. Examplesare methoxy, ethoxy, propoxy, butoxy and pentoxy.

“Aryl” is an aromatic hydrocarbon. Examples include phenyl and naphthyl.

“Heteroatom” generally is an atom that differs from those that typify amolecule. Thus, in a hydrocarbon, any atom not a carbon or a hydrogen isa heteroatom. Common biologically acceptable heteroatoms include oxygen,sulfur and nitrogen.

The term “heteroaryl” relates to an aryl group where one or more carbonatoms is replaced with a heteroatom. Examples are pyridyl, imidazolyl,pyrrolyl, thienyl, furyl, pyranyl, pyrimidinyl, pyridazinyl, indolyl,quinolyl, naphthyridinyl and isoxazoyl.

The term “cycloalkyl” refers to a cyclic hydrocarbon. Some examples arecyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl.

“Heterocycle” is a cycloalkyl where one or more carbon atoms arereplaced with a heteroatom. Examples are pyrrolidinyl, piperidinyl andpiperazinyl.

The term “heteroalkyl” is an alkyl where one or more carbon atoms arereplaced with a heteroatom. An ether is a heteroalkyl.

By “substituted” is meant that the base organic radical has one or moresubstituent groups. Thus, an atom or group replaces another atom orgroup in a molecule. Representative substituents include a halogen,C1-C8 alkyl, —CN, alkoxyl, hydroxyl, sulfide, sulfate, sulfonamide,amine, amide, an alcohol, a keto group, C6-C18 aryl, a halogenatedC1-C18 alkyl, a nitrite group or a nitrate group.

A “halogen” is, for example, chlorine, fluorine or bromine.

An “alkenyl” is a hydrocarbon containing one or more carbon-carbondouble bonds. The hydrocarbon can be branched.

The term “ring” means one or one of a plurality of ring structures,where two or more of the plurality of rings can be fused, wherein the orone or more of the plurality of rings may be aromatic, contain aheteroatom, may be substituted or a combination thereof. The ring may bebicyclic or polycyclic, and may contain a bridge.

The compounds of interest bind HM74 and activate HM74, but do not bindto HM74A.

The oxydecalins of interest can be synthesized as known in the art, U.S.Pat. No. 6,399,653.

Oxydecalin-like compounds of the invention can be incorporated intopharmaceutical compositions suitable for administration. Suchcompositions typically comprise the active ingredient and apharmaceutically acceptable carrier. As used herein, the language“pharmaceutically acceptable carrier” is intended to include any and allsolvents, dispersion media, coatings, antibacterial and antifungalagents, isotonic and absorption delaying agents and the like, compatiblewith pharmaceutical administration. The use of such media and agents forpharmaceutically active substances is well known in the art. Exceptinsofar as any conventional media or agent is incompatible with theactive compound, use thereof in the compositions is contemplated.Supplementary active compounds also can be incorporated into thecompositions.

A pharmaceutical composition of the invention is formulated to becompatible with the intended route of administration. Examples of routesof administration include parenteral, e.g., intravenous, intradermal,subcutaneous, oral (e.g., inhalation), transdermal (topical),transmucosal and rectal administration. Solutions or suspensions usedfor parenteral, intradermal or subcutaneous application can include thefollowing components: a sterile diluent such as water for injection,saline solution, fixed oils, polyethylene glycols, glycerine, propyleneglycol or other synthetic solvents; antibacterial agents such as benzylalcohol or methyl parabens; antioxidants such as ascorbic acid or sodiumbisulfite; chelating agents such as EDTA; buffers such as acetates,citrates or phosphates and agents for the adjustment of tonicity such assodium chloride or dextrose. pH can be adjusted with acids or bases,such as HCl or NaOH. The parenteral preparation can be enclosed inampoules, disposable syringes or multiple dose vials made of glass orplastic.

Pharmaceutical compositions suitable for injectable use include sterileaqueous solutions (where water soluble) or dispersions and sterilepowders for the extemporaneous preparation of sterile injectablesolutions or dispersions. For intravenous administration, suitablecarriers include physiological saline, bacteriostatic water, CremophorEL® (BASF; Parsippany, N.J.) or phosphate-buffered saline (PBS). In allcases, the composition must be sterile and should be fluid to the extentthat easy syringability exists. The composition must be stable under theconditions of manufacture and storage and must be preserved against thecontaminating action of microorganisms such as bacteria and fungi. Thecarrier can be a solvent or dispersion medium containing, for example,water, ethanol, polyol (for example, glycerol, propylene glycol andliquid polyetheylene glycol and the like) and suitable mixtures thereof.The proper fluidity can be maintained, for example, by the use of acoating such as lecithin, by the maintenance of the required particlesize in the case of dispersion and by the use of surfactants. Preventionof the action of microorganisms can be achieved by various antibacterialand antifungal agents, for example, parabens, chlorobutanol, phenol,ascorbic acid, thimerosal and the like. In many cases, it will bepreferable to include isotonic agents, for example, sugars, polyalcoholssuch as mannitol, sorbitol or sodium chloride in the composition.Prolonged absorption of the injectable compositions can be brought aboutby including in the composition an agent that delays absorption, forexample, aluminum monostearate and gelatin.

Sterile injectable solutions can be prepared by incorporating the activecompound in the required amount in an appropriate solvent with one or acombination of ingredients enumerated above, as required, followed byfiltered sterilization. Generally, dispersions are prepared byincorporating the active compound into a sterile vehicle that contains abasic dispersion medium and the required other ingredients from thoseenumerated above. In the case of sterile powders for the preparation ofsterile injectable solutions, the preferred methods of preparation arevacuum drying and freeze drying that yield a powder of the activeingredient plus any additional desired ingredient from a previouslysterile-filtered solution thereof.

Oral compositions generally include an inert diluent or an ediblecarrier. The compositions can be enclosed in gelatin capsules orcompressed into tablets. For the purpose of oral therapeuticadministration, the active compound can be incorporated with excipientsand used in the form of tablets, troches or capsules. Oral compositionsalso can be prepared using a fluid carrier to yield a syrup or liquidformulation, or for use as a mouthwash, wherein the compound in thefluid carrier is applied orally and swished and expectorated orswallowed.

Pharmaceutically compatible binding agents, and/or adjuvant materialscan be included as part of the composition. The tablets, pills,capsules, troches and the like can contain any of the followingingredients or compounds of a similar nature: a binder such asmicrocrystalline cellulose, gum tragacanth or gelatin; an excipient suchas starch or lactose, a disintegrating agent such as alginic acid,Primogel or corn starch; a lubricant such as magnesium stearate orSterotes; a glidant such as colloidal silicon dioxide; a sweeteningagent such as sucrose or saccharin; or a flavoring agent such aspeppermint, methyl salicylate or orange flavoring.

For administration by inhalation, the compounds are delivered in theform of an aerosol spray from a pressurized container or dispenser thatcontains a suitable propellant, e.g., a gas such as carbon dioxide or anebulizer.

Systemic administration also can be by transmucosal or transdermalmeans. For transmucosal or transdermal administration, penetrantsappropriate to the barrier to be permeated are used in the formulation.Such penetrants generally are known in the art and include, for example,for transmucosal administration, detergents, bile salts and fusidic acidderivatives. Transmucosal administration can be accomplished through theuse of nasal sprays or suppositories. For transdermal administration,the active compounds are formulated into ointments, salves, gels orcreams as generally known in the art.

The compounds also can be prepared in the form of suppositories (e.g.,with conventional suppository bases such as cocoa butter and otherglycerides) or retention enemas for rectal delivery.

In one embodiment, the active compounds are prepared with carriers thatwill protect the compound against rapid elimination from the body, suchas a controlled release formulation, including implants andmicroencapsulated delivery systems. Biodegradable, biocompatiblepolymers can be used, such as ethylene vinyl acetate, polyanhydrides,polyglycolic acid, collagen, polyorthoesters and polylactic acid.

Methods for preparation of such formulations will be apparent to thoseskilled in the art.

The materials also can be obtained commercially from Alza Corporationand Nova Pharmaceuticals, Inc. Liposomal suspensions (includingliposomes targeted to infected cells with monoclonal antibodies) alsocan be used as pharmaceutically acceptable carriers. Those can beprepared according to methods known to those skilled in the art, forexample, as described in U.S. Pat. No. 4,522,811.

It is especially advantageous to formulate oral or parenteralcompositions in dosage unit form for ease of administration anduniformity of dosage. Dosage unit form as used herein refers tophysically discrete units suited as unitary dosages for the subject tobe treated; each unit containing a predetermined quantity of activecompound calculated to produce the desired therapeutic effect inassociation with the required pharmaceutical carrier. Depending on thetype and severity of the disease, about 1 μg/kg to 15 mg/kg (e.g., 0.1to 20 mg/kg) of active ingredient is an initial candidate dosage foradministration to the patient, whether, for example, by one or moreseparate administrations or by continuous infusion. A typical dailydosage might range from about 1 μg/kg to 100 mg/kg or more, depending onthe factors mentioned above. For repeated administrations over severaldays or longer, depending on the condition, the treatment is sustaineduntil a desired suppression of disease symptoms occurs. However, otherdosage regimens may be useful. The progress of the therapy is monitoredeasily by conventional techniques and assays. An exemplary dosingregimen is disclosed in WO 94/04188. The specification for the dosageunit forms of the invention is dictated by and directly dependent on theunique characteristics of the active compound and the particulartherapeutic effect to be achieved and the limitations inherent in theart of compounding such an active compound for the treatment ofindividuals.

The pharmaceutical compositions can be included in a container, pack ordispenser together with instructions for administration.

The HM74 modulators of interest can be used in screening assays andmethods of treatment (e.g., therapeutic and prophylactic). The HM74modulators of interest can be used to screen for other drugs orcompounds that modulate HM74 activity or expression as well as to treatdisorders characterized by inflammation. The modulators of interest mayalso find use in conditions resulting from insufficient or excessiveproduction of HM74 protein or by production of HM74 protein forms thathave decreased or aberrant activity compared to HM74 wild-type protein.The invention further pertains to novel HM74 modulators identified bythe screening assays and uses thereof for treatments as describedherein.

The invention provides a method (also referred to herein as a “screeningassay”) for identifying modulators, i.e., candidate or test compounds oragents (e.g., peptides, peptidomimetics, small molecules, antibodies orother drugs) that bind to HM74 and have a stimulatory or inhibitoryeffect on, for example, HM74 expression or HM74 activity.

In one embodiment, the invention provides assays for screening candidateor test compounds that bind to or modulate the activity of HM74. Thus,the screening assays can be used to identify other furosemide-like andoxydecalin-like compounds that modulate HM74. Such modulators also canbe used in competition assays to identify other modulators such as HM74antagonists.

In one embodiment, an assay is a cell-based assay in which a cell thatexpresses a membrane-bound form of HM74 on the cell surface is contactedwith a test compound and the ability of the test compound to activateHM74 is determined. The cell, for example, can be a yeast cell or a cellof mammalian origin. Determining the ability of the test compound toactivate HM74 can be accomplished, for example, by coupling the testcompound with a radioisotope or enzymatic label such that binding of thetest compound to HM74 can be determined by detecting the labeledcompound in a complex with HM74, or where HM74 is located. For example,test compounds can be labeled with 125I, 35S, 14C or 3H, either directlyor indirectly and the radioisotope detected by direct counting ofradioemmission or by scintillation counting. Alternatively, testcompounds can be labeled enzymatically with, for example, horseradishperoxidase, alkaline phosphatase or luciferase and the enzymatic labeldetected by determination of conversion of an appropriate substrate toproduct. In a preferred embodiment, the assay comprises contacting acell that expresses a membrane-bound form of HM74 on the cell surfacewith a known compound that binds HM74 along with a test compound anddetermining the ability of the test compound to compete with the knowncompound to interact with an HM74.

In another embodiment, an assay is a cell-based assay comprisingcontacting a cell expressing a membrane-bound form of HM74 on the cellsurface with a test compound and determining the ability of the testcompound to modulate (e.g., stimulate or inhibit) the activity of HM74.Determining the ability of the test compound to modulate the activity ofHM74 can be accomplished, for example, by determining the ability of thetest compound to activate or to inhibit HM74. That might be manifestwhen activated HM74 interacts with an intracellular or membrane targetmolecule associated with the signaling pathway. As used herein, a“target molecule” is a molecule with which HM74 binds or interacts innature, for example, a molecule on the surface of a cell that expressesan HM74, a molecule on the surface of a second cell, a molecule in theextracellular milieu, a molecule associated with the internal surface ofa cell membrane or a cytoplasmic molecule. An HM74 target molecule canbe a non-HM74 molecule. In one embodiment, an HM74 target molecule is acomponent of a signal transduction pathway that facilitates transductionof an extracellular signal (e.g., a signal generated by binding of acompound to HM74) through the cell membrane and into the cell. Thetarget, for example, can be a second intercellular protein that hascatalytic activity or a protein that facilitates the association ofdownstream signaling molecules with HM74.

Determining the ability of the HM74 to bind to or to interact with anHM74 target molecule can be accomplished by one of the methods describedabove for determining direct binding. In a preferred embodiment,determining the ability of HM74 to bind to or to interact with an HM74target molecule can be accomplished by determining the activity of thetarget molecule. For example, the activity of the target molecule can bedetermined by detecting induction of a cellular second messenger of thetarget (e.g., intracellular Ca2+, diacylglycerol, IP3 etc.), detectingcatalytic/enzymatic activity of the target on an appropriate substrate,detecting the induction of a reporter gene (e.g., an HM74-responsiveregulatory element operably linked to a nucleic acid encoding adetectable marker, e.g. luciferase) or detecting a cellular response,for example, cellular differentiation or cell proliferation.

In yet another embodiment, an assay of the instant invention is acell-free assay comprising contacting HM74 with a test compound anddetermining the ability of the test compound to bind to the HM74.Binding of the test compound to HM74 can be determined either directlyor indirectly as described above. In a preferred embodiment, the assayincludes contacting HM74 with a known compound of the invention alongwith a test compound and determining the ability of the test compound toimpact the HM74 activity of the known compound described herein.Determining the ability of the test compound to interact with HM74comprises determining the ability of the test compound to preferentiallybind to HM74 as compared to the binding of the known compound describedherein.

In another embodiment, an assay is a cell-free assay comprisingcontacting HM74 with a test compound and determining the ability of thetest compound to modulate (e.g., stimulate or inhibit) the activity ofthe HM74. Determining the ability of the test compound to modulate theactivity of HM74 can be accomplished, for example, by determining theability of the activated HM74 to bind to an HM74 target molecule by oneof the methods described above for determining direct binding. In analternative embodiment, determining the ability of the test compound tomodulate the activity of HM74 can be accomplished by determining theability of the HM74 to further modulate an HM74 target molecule. Forexample, the catalytic/enzymatic activity of the target molecule on anappropriate substrate can be determined as described previously.

In yet another embodiment, the cell-free assay comprises contacting HM74with a known compound that binds HM74 with a test compound anddetermining the ability of the test compound to interact with an HM74,wherein determining the ability of the test compound to interact with anHM74 comprises determining the ability of HM74 preferentially to bind toor to modulate the activity of an HM74 target molecule.

Receptors can be activated by non-ligand molecules that necessarily donot inhibit ligand binding but cause structural changes in the receptorto enable G protein binding or, perhaps receptor aggregation,dimerization or clustering that can cause activation.

The cell-free assays of the instant invention are amenable to use ofboth the soluble form and the membrane-bound form of HM74. In the caseof cell-free assays comprising the membrane-bound form of HM74, it maybe desirable to utilize a solubilizing agent such that themembrane-bound form of HM74 is maintained in solution. Examples of suchsolubilizing agents include non-ionic detergents such asn-octylglucoside, n-dodecylglucoside, n-dodecylmaltoside,octanoyl-N-methylglucamide, decanoyl-N-methylglucamide, Triton X-100,Triton X-114, Thesit®, isotridecylpoly(ethylene glycol ether)n,3-[(3-cholamidopropyl)dimethylammino]-1l-propane sulfonate (CHAPS),3-[(3-cholamidopropyl)dimethylammino]-2-hydroxy-1-propane sulfonate(CHAPSO) or N-dodecyl=N,N-dimethyl-3-ammonio-1-propane sulfonate.

In another embodiment, HM74 is altered to be in a constant active statewhen expressed on a host cell. Altering HM74 can make the receptoractive without having to bind ligand. One way to achieve an activatedreceptor is to alter HM74 to interact with G proteins without ligandbinding. The alteration mimics the conformational changes of thereceptor on ligand binding that enables the receptor to bindintracellular G proteins. One such approach is provided in WO 00/22129.

WO 00/22129 teaches particular amino acids in the region of TM6 and IC3that yield constitutive activity. The methods for incorporating theparticular amino acids into HM74 are known in the art, such assite-directed mutagenesis, subcloning and so on. The altered HM74molecule then is expressed in a host cell to yield a constitutivelyactive HM74.

The activated cell then is exposed to molecules suspected of being HM74agonists, antagonists, inverse agonists and so on, molecules that alterHM74 activity. Those molecules that alter G protein activity aretargeted for treating disorders associated with altered HM74 metabolismusing methods known in pharmaceutic development.

In more than one embodiment of the above assay methods of the instantinvention, it may be desirable to immobilize either HM74 or a targetmolecule thereof to facilitate separation of complexed from uncomplexedforms of one or both of the proteins, as well as to accommodateautomation of the assay. Binding of a test compound to HM74 orinteraction of HM74 with a target molecule in the presence and absenceof a candidate compound, can be accomplished in any vessel suitable forcontaining the reactants. Examples of such vessels include microtitreplates, test tubes and microcentrifuge tubes. In one embodiment, afusion protein can be provided that adds a domain that allows one orboth of the proteins to be bound to a matrix. For example,glutathione-S-transferase/HM74 fusion proteins orglutathione-S-transferase/target fusion proteins can be adsorbed ontoglutathione Sepharose® beads (Sigma Chemical, St. Louis, Mo.) orglutathione-derivatized microtitre plates. That complex then arecombined with the test compound and either the non-adsorbed targetprotein or HM74 protein and the mixture incubated under conditionsconducive to complex formation (e.g., at physiological conditions forsalt and pH). Following incubation, the beads or microtitre plate wellsare washed to remove any unbound components and complex formation ismeasured either directly or indirectly, for example, as described above.Alternatively, the complexes can be dissociated from the matrix and thelevel of HM74 binding or activity determined using standard techniques.

Other techniques for immobilizing proteins on matrices also can be usedin the screening assays of the invention. For example, either HM74 or atarget molecule thereof can be immobilized utilizing conjugation ofbiotin and streptavidin. Biotinylated HM74 or target molecules can beprepared from biotin-NHS (N-hydroxy-succinimide) using techniques wellknown in the art (e.g., biotinylation kit, Pierce Chemicals, Rockford,Ill.) and immobilized in the wells of streptavidin-coated 96-well plates(Pierce Chemicals). Alternatively, antibodies reactive with HM74 ortarget molecules but that do not interfere with binding of the HM74protein to a target molecule can be derivatized to the wells of theplate and unbound target or HM74 trapped in the wells by antibodyconjugation. Methods for detecting such complexes, in addition to thosedescribed above for the GST-immobilized complexes, includeimmunodetection of complexes using antibodies reactive with HM74 ortarget molecule, as well as enzyme-linked assays that rely on detectingan enzymatic activity associated with the HM74 or target molecule.

In another embodiment, modulators of HM74 expression are identified in amethod in which a cell is contacted with a candidate compound and theexpression of HM74 mRNA or protein in the cell is determined. The levelof expression of HM74 mRNA or protein in the presence of the candidatecompound is compared to the level of expression of HM74 mRNA or proteinin the absence of the candidate compound. The candidate compound thencan be identified as a modulator of HM74 expression based on thatcomparison. For example, when expression of HM74 mRNA or protein isgreater (statistically significantly greater) in the presence of thecandidate compound than in the absence thereof, the candidate compoundis identified as a stimulator or agonist of HM74 mRNA or proteinexpression. Alternatively, when expression of HM74 mRNA or protein isless (statistically significantly less) in the presence of the candidatecompound than in the absence thereof, the candidate compound isidentified as an inhibitor or antagonist of HM74 mRNA or proteinexpression. If HM74 activity is reduced in the presence of ligand oragonist, or in a constitutive HM74, below baseline, the candidatecompound is identified as an inverse agonist. The level of HM74 mRNA orprotein expression in the cells can be determined by methods describedherein for detecting HM74 mRNA or protein.

As large quantities of pure HM74 can be made, physical characterizationof the conformation of areas of likely function can be ascertained forrational drug design. For example, the IC3 region of the molecule and ECdomains are regions of particular interest. Once the shape and ionicconfiguration of a region are discerned, candidate drugs that interactwith those regions can be configured and then tested in intact cells,animals and patients. Methods that would enable deriving such structureinformation include X-ray crystallography, NMR spectroscopy, molecularmodeling and so on. The 3-D structure also can lead to identification ofanalogous conformational sites in other known proteins where known drugsthat act at a particular site exist. Those drugs, or derivativesthereof, may find use with HM74.

The invention further pertains to novel agents identified by theabove-described screening assays and uses thereof for treatments asdescribed herein.

The instant invention provides for both prophylactic and therapeuticmethods of treating a subject at risk of (or susceptible to) a disorderor having a disorder associated with aberrant HM74 expression oractivity. Such disorders include, but are not limited to, for example,inflammatory disorders such as asthma, chronic obstructive pulmonarydisease and rheumatoid arthritis.

In one aspect, the invention provides a method for preventing in asubject, a disease or condition associated with an aberrant HM74expression or activity, by administering to the subject an agent thatmodulates HM74 expression or at least one HM74 activity. Subjects atrisk for a disease that is caused by or contributed to by aberrant HM74expression or activity can be identified by, for example, any or acombination of diagnostic or prognostic assays as described herein.Administration of a prophylactic agent can occur prior to themanifestation of symptoms characteristic of the HM74 aberrancy, suchthat a disease or disorder is prevented or, alternatively, delayed inprogression. Depending on the type of HM74 aberrancy, for example, anHM74 agonist or HM74 antagonist agent can be used for treating thesubject. The appropriate agent can be determined based on screeningassays described herein.

Another aspect of the invention pertains to methods of modulating HM74expression or activity for therapeutic purposes. The modulatory methodof the invention involves contacting a cell with an agent that modulatesone or more of the activities of HM74 associated with the cell. An agentthat modulates HM74 activity can be an agent as described herein, suchas a furosemide or oxydecalin, nucleic acid or a protein, anaturally-occurring cognate ligand of an HM74 protein, a peptide, anHM74 peptidomimetic or other small molecule. In one embodiment, theagent stimulates one or more of the biological activities of HM74. Inanother embodiment, the agent inhibits one or more of the biologicalactivities of HM74 protein. Examples of such inhibitory agents includeanti-HM74 antibodies. The modulatory methods can be performed in vitro(e.g., by culturing the cell with the agent) or, alternatively, in vivo(e.g., by administering the agent to a subject). As such, the instantinvention provides methods of treating an individual afflicted with adisease or disorder characterized by aberrant expression or activity ofan HM74. In one embodiment, the method involves administering an agent(e.g., an agent identified by a screening assay described herein) orcombination of agents that modulates (e.g., upregulates ordownregulates) HM74 expression or activity.

Stimulation of HM74 activity is desirable in situations in which HM74 isdownregulated abnormally and/or in which increased HM74 activity islikely to have a beneficial effect. Conversely, inhibition of HM74activity is desirable in situations in which HM74 is upregulatedabnormally and/or in which decreased HM74 activity is likely to have abeneficial effect.

The invention is illustrated further by the following examples whichshould not be construed as limiting. The contents of all references,patents and published patent applications cited throughout theapplication hereby are incorporated by reference.

EXAMPLE 1 Generation of Mammalian Cells Expressing HM74

The cDNA encoding hHM74 is cloned into an expression vector andtransfected into mammalian cells, such as CHO cells or 293 cells.

To generate mammalian cells overexpressing HM74, mammalian cells areplated in a six-well 35 mm tissue culture plate (3×105 mammalian cellsper well (ATCC Catalog No. CRL-1573)) in 2 ml of DMEM media (Gibco/BRL,Catalog No. 11765-054) in the presence of 10% fetal bovine serum(Gibco/BRL Catalog No. 1600-044).

The cells then are incubated at 37° C. in a CO2 incubator until thecells are 50-80% confluent. The cloned cDNA nucleic acid sequence ofHM74 is inserted in a pcDNA 3.1 cloning vector (Invitrogen, Catalog No.V790-20). Two μg of the DNA are diluted into 100 μl of serum-free F12Ham's medium. Separately, 25 μl of Lipofectamine Reagent (LifeTechnologies, Catalog No. 18324-020) is diluted into 100 μl ofserum-free F12 Ham's medium. The DNA solution and the Lipofectaminesolution then are mixed gently and incubated at room temperature for 45minutes to allow for the formation of DNA-lipid complexes.

The cells are rinsed once with 2 ml of serum-free F12 Ham's medium. Foreach transfection (six transfections in a six-well plate), 0.8 ml ofserum-free F12 Ham's medium are added to the solution containing theDNA-lipid complexes (0.2 ml total volume) and mixed gently. Theresulting mixture (hereinafter the “transfection mixture”) then isoverlaid (0.8 ml+0.2 ml) onto the rinsed cells. No anti-bacterialreagents are added. The cells then are incubated with the lipid-DNAcomplexes for 16 hours at 37° C. in a CO2 incubator to allow fortransfection.

After the completion of the incubation period, 1 ml of F12 Ham's mediumcontaining 10% fetal bovine serum is overlaid onto the cells withoutfirst removing the transfection mixture. At 18 hours after transfection,the media overlaying the cells is aspirated. Cells then are washed withPBS, pH 2-4 (Gibco/BRL Catalog No. 10010-023) and the PBS is replacedwith F12 Ham's medium containing 5% serum (“selective media”). At 72hours after transfection, the cells are diluted ten-fold into theselective medium containing the antibacterial agent genetecin at 400μg/ml (Life Technologies, Catalog No. 11811).

EXAMPLE 2 Agonist Assay

To screen for agonists of human HM74, HM74 can be coupled artificiallyto a G_(q) mechanism. Activation of the G_(q) mechanism stimulates therelease of Ca²⁺ from sarcoplasmic reticulum vesicles within the cell.The Ca²⁺ is released into the cytoplasm where it can be detected usingCa²+ chelating dyes. A Fluorometric Imaging Plate Reader or FLIPR®apparatus (Molecular Devices) is used to monitor any resulting changesin fluorescence. The activity of an agonist is reflected by any increasein fluorescence.

CHO-K1 cells expressing HM74 are pre-engineered to express anindiscriminate form of Gq protein (Gα16). To prepare such cells,Gα16-coupled CHO cells are obtained commercially (Molecular DevicesLIVEWARETM cells, Catalog No. RD-HGA16) and the protocol in Example 1,followed to facilitate expression of HM74 in those cells.

The cells are maintained in log phase of growth at 37° C. and 5% CO2 inF12 Ham's media (Gibco/BRL, Catalog No. 11765-054) containing 10% fetalbovine serum, 100 lU/ml penicillin (Gibco/BRL, Catalog No. 15140-148),100 μg/ml streptomycin (Catalog No. 15140-148, Gibco/BRL), 400 μg/mlgeneticin (G418) (Gibco/BRL, Catalog No. 10131-035) and 200 μg/ml zeocin(Invitrogen, Catalog No. R250-05). One day prior to an assay, 12,500cells/well of the CHO-K1 cells are plated onto 384-well clear-bottomedassay plates with a well volume of 50 μl (Greiner/Marsh, Catalog No.N58102) using a 96/384 Multidrop device (Labsystems, Type 832). Thecells are incubated at 37° C. in a humidified 5% CO2 incubator (FormaScientific CO2 water-jacketed incubator Model 3110).

The following stock solutions are prepared: a 1 M stock solution ofHepes (pH 7.5) (Gibco/BRL, Catalog No. 15630-080); a 250 mM stocksolution of probenicid (Sigma, Catalog No. P8761) made in 1 N NaOH; anda 1 mM stock solution of Fluo 4-AM Dye (Molecular Probes, Catalog No. Fl4202) made in DMSO (Sigma D2650). Reaction buffer is prepared with 1000ml Hank's balanced salt solution (Fisher/Mediatech, Catalog No.MT21023), 20 ml of the 1 M Hepes stock solution and 10 ml of the 250 mMprobenicid stock solution. To prepare the loading buffer, 1.6 ml of the1 mM Fluo 4-AM Dye stock solution is mixed with 0.32 ml of pluronic acid(Molecular Probes, Catalog No. P6866) and then mixed with 400 ml of theabove reaction buffer and 4 ml of fetal bovine serum.

One hour prior to the assay, 50 μl of freshly-prepared loading buffer isadded to each well of the 384-well plate using a 96/384 Multidropdevice. The cells are incubated at 37° C. in a humidified incubator tomaximize dye uptake. Immediately prior to the assay, the cells arewashed 2 times with 90 μl of reaction buffer using a 384 EMBLA CellWasher (Skatron; Model No. 12386) with the aspiration head set at least10 mm above the plate bottom, leaving 45 μl of buffer per well.

The CCD camera (Princeton Instruments) of the FLIPR® II (MolecularDevices) instrument is set at an f-stop of 2.0 and an exposure of 0.4seconds. The camera is used to monitor the cell plates for accuracy ofdye loading.

A compound library containing possible oxydecalin-like compounds istested at a concentration of about 10 μM each in physiological saltbuffer per well. Changes in fluorescence are measured for 10 secondsprior to compound addition. After the addition of the compound,fluorescence is measured every second for the first minute followed byexposures taken every six seconds for a total experimental analysis timeof three minutes. Five μl aliquots of the 100 μM stock compound areadded after the tenth scan, giving a final compound concentration on thecells of 10 μM. The maximum fluorescence changes for the first 80 scansare recorded as a measure of agonist activity and compared to themaximum fluorescence change induced by 10 μM ATP (Sigma A9062).

A number of oxydecalin compounds were found to activate HM74.

EXAMPLE 3 Antagonist Assay

To screen for antagonists of human HM74, HM74 can be coupledartificially to a G_(q) mechanism. As in Example 2, a FLIPR® apparatusis used to monitor any resulting changes in fluorescence. The activityof an antagonist is reflected by any decrease in fluorescence.

CHO-K1 cells expressing HM74 are pre-engineered to express anindiscriminate form of Gq protein (Gα16), as described in Example 2. Thecells are maintained in log phase of growth at 37° C. and 5% CO2 in F12Ham's medium (Gibco/BRL, Catalog No. 11765-054) containing 10% fetalbovine serum, 100 IU/ml penicillin (Gibco/BRL, Catalog No. 15140-148),100 μg/ml streptomycin (Catalog No. 15140-148, Gibco/BRL), 400 μg/mlgeneticin (G418) (Gibco/BRL, Catalog No. 10131-035) and 200 μg/ml zeocin(Invitrogen, Catalog No. R250-05). One day prior to the assay, 12,500cells/well of the CHO-K1 cells are plated onto 384-well black/clearbottomed assay plates with a well volume of 50 μl (Greiner/Marsh,Catalog No. N58102) using a 96/384 Multidrop device. The cells areallowed to incubate at 37° C. in humidified 5% CO2.

The following stock solutions are prepared: a 1 M stock solution ofHepes (pH 7.5) (Gibco/BRL, Catalog No. 15630-080); a 250 mM stocksolution of probenicid (Sigma, Catalog No. P8761) made in 1 N NaOH; a 1mM stock solution of Fluo 4-AM Dye (Molecular Probes, Catalog No. F14202) made in DMSO (Sigma D2650); and a stock solution of ligand orantagonist. Reaction buffer is prepared with 1000 ml Hank's balancedsalt solution (Fisher/Mediatech, Catalog No. MT21023), 20 ml of the 1 MHepes stock solution, 10 ml of the 250 mM probenicid stock solution and1 mM CaCl2. To prepare the loading buffer, 80 μl of the 1 mM Fluo 4-AMDye stock solution is mixed with 16 μl of pluronic acid (MolecularProbes, Catalog No. P6866) and then mixed with 20 ml of the abovereaction buffer and 0.2 ml of fetal bovine serum.

Thirty minutes prior to the assay, 30 μl of freshly-prepared loadingbuffer is added to each well of the 384-well plate using a 96/384Multidrop device. The cells are incubated at 37° C. in a humidified CO2incubator to maximize dye uptake. Immediately prior to the assay, thecells are washed 3 times with 100 μl of reaction buffer using a 384EMBLA Cell Washer with the aspiration head set at least 40 mm above theplate bottom, leaving 45 μl of buffer per well.

Five μl of the 100 μM stock antagonist compound are added to the cellsusing a Platemate-384 pipetor (Matrix). The compound concentrationduring the incubation step is approximately 10 μM. The cells are placedon the FLIPR® II and plate fluorescence is measured every second for thefirst minute followed by exposures taken every six seconds for a totalexperimental analysis time of three minutes. Antagonist or ligand (10μM) is added after the tenth scan. After each addition, the 384 tips arewashed 10 times with 20 μl of 0.01% DMSO in water.

The HM74 cells either can be exposed to an identified agonist or notprior to testing with candidate antagonists.

EXAMPLE 4 Receptor Binding Assay

To prepare membrane fractions containing HM74, CHO cell lines expressingHM74 are harvested by incubation in phosphate-buffered saline (10 ml)containing 1 mM EDTA. The cells are washed further 3 times inphosphate-buffered saline containing 1 mM EDTA (10 ml) prior toresuspension in 5 ml of Buffer A (50 mM Tris-HCI (pH 7.8) (Sigma T6791),5 mM MgCl2 (Sigma M8266) and 1 mM EGTA (Sigma 0396).

The cells then are disrupted with a tissue homogenizer (Polytron,Kinemetica, Model PT 10/35) for 1 minute. The resulting homogenate iscentrifuged in a Sorvall Instruments RC3B refrigerated centrifuge at49,000×g at 4° C. for 20 minutes. The resulting pellet is resuspended in25 ml of Buffer A and the centrifugation step is repeated three times.Following the final centrifugation, the pellet again is resuspended in 5ml of Buffer A, aliquoted and stored at −70° C.

A receptor binding assay using the membrane fraction and a radiolabeledagonist of interest as a tracer is performed. The assay is performed ina 96-well plate (Beckman Instruments). The binding reaction consists of18 μg of the CHO cell preparation in the presence of radioactive agonist(0.01 nM-25 nM) in a final volume of 0.2 ml of Buffer A containing 0.1%bovine serum albumin (Sigma, Catalog No. 34287) (see Im et al., J. Biol.Chem. (2000) 275(19): 14281-14286). The reaction is incubated for 1 hourat room temperature. The reaction is terminated by filtration throughWhatman GF/C filters on a multichannel harvester (Brandell) that ispretreated with 0.3% polyethyleneimine (Sigma, Catalog No. P3143) and0.1% bovine serum albumin (BSA) for 1 hour. The mixture is applied tothe filter and incubated for one hour. The filters are washed 6 timeswith 1 ml of ice cold 50 mM Tris-HCl, pH 7.6. Specific binding iscalculated based on the difference between total binding andnon-specific binding (background) for each tracer concentration bymeasuring the radioactivity. Eight to 16 concentration data points areobtained to determine the binding of agonist to the receptor achieved inan equilibrium state between the agonist and receptor (equilibriumbinding parameters). In a competitive assay, a test compound is added tothe mixture to compete for the binding of radioactive agonist on thereceptor (competition binding values). Inhibition curves are prepared todetermine the concentration required to achieve a 50% inhibition ofbinding (IC50).

EXAMPLE 5 Small Molecule Agonists

A series of oxydecalin-like molecules were exposed to cells expressingHM74 as described above. Target molecules were labeled to determinewhether binding to HM74 occurred. Binding was detected by determiningthe degree of labeling of the cells following washing. Binding also wasascertained by isolating HM74 by 2-D gel electrophoresis and determiningthe degree of labeling associated with that protein. Following thatbinding assessment, or independent of that binding assessment, theability of a candidate agonist to activate HM74 was determined. TheFLIPR assay was used to assess intracellular calcium mobilization onbinding of target molecule to HM74. Thus, oxydecalin molecules thatcaused calcium mobilization were identified.

The invention now having been described, the artisan will know thatvarious changes and modifications can be make to the teachings hereinwithout departing from the spirit and scope of the invention taughtherein.

All references cited herein are incorporated by reference in entiretyherein.

1. A therapeutic method for modulating HM74 signaling activity or signaltransduction in a patient in need of treatment comprising administeringto said patient a molecule having the structure:

where X is O, NR₂ or S; R₁ is a C₁-C₁₈ alkyl, which may be branched, maycontain a heteroatom or may be substituted, or combinations thereof; aC₁-C₁₈ alkenyl, which may be branched, may contain a heteroatom or maybe substituted, or combinations thereof; a C₁-C₁₈ alkynl, which may bebranched, may contain a heteroatom or may be substituted, orcombinations thereof; a C₃-C₁₈ aryl which may contain a side group, maycontain a bridge, may contain a heteroatom or may be substituted, orcombinations thereof; or a C₅-C₁₈ cycloalkyl which may contain a sidegroup, may contain a bridge, may contain a heteroatom or may besubstituted, or combinations thereof; or combinations thereof; R2 is anR1 group, a (C1-C10) alkyl-(C3-C10) cycloalkyl, which may be branched,may contain a heteroatom or may be substituted, or combinations thereof;or X and R2 may form a ring; R3 is H or R1; and Y is carbonyl, a Schiffbase, an oxine, a ketal, an acetal, an oxazolidine, a thiazolidine or anenol ester.
 2. A method for identifying an agonist of HM74 comprising,contacting a potential agonist with a cell expressing HM74 anddetermining whether in the presence of said potential agonist thesignaling activity of HM74 is increased relative to the activity of HM74in the absence of said potential agonist, wherein said potential agonisthas the structure:

where X is O, NR₂ or S; R₁ is a C₁-C₁₈ alkyl, which may be branched, maycontain a heteroatom or may be substituted, or combinations thereof; aC₁-C₁₈ alkenyl, which may be branched, may contain a heteroatom or maybe substituted, or combinations thereof; a C₁-C₁₈ alkynl, which may bebranched, may contain a heteroatom or may be substituted, orcombinations thereof; a C₃-C₁₈ aryl which may contain a side group, maycontain a bridge, may contain a heteroatom or may be substituted, orcombinations thereof; or a C₅-C₁₈ cycloalkyl which may contain a sidegroup, may contain a bridge, may contain a heteroatom or may besubstituted, or combinations thereof; or combinations thereof; R2 is anR1 group, a (C1-C10) alkyl-(C3-C10) cycloalkyl, which may be branched,may contain a heteroatom or may be substituted, or combinations thereof;or X and R2 may form a ring; R3 is H or R1; and Y is carbonyl, a Schiffbase, an oxine, a ketal, an acetal, an oxazolidine, a thiazolidine or anenol ester.
 3. A method for identifying an inverse agonist of HM74comprising, contacting a potential inverse agonist with a cellexpressing HM74 and determining whether in the presence of saidpotential inverse agonist, the activity of HM74 is decreased relative tothe activity of HM74 in the absence of said potential inverse agonist,and is decreased in the presence of an agonist, wherein said potentialinverse agonist has the structure:

where X is O, NR₂ or S; R₁ is a C₁-C₁₈ alkyl, which may be branched, maycontain a heteroatom or may be substituted, or combinations thereof; aC₁-C₁₈ alkenyl, which may be branched, may contain a heteroatom or maybe substituted, or combinations thereof; a C₁-C₁₈ alkynl, which may bebranched, may contain a heteroatom or may be substituted, orcombinations thereof; a C₃-C₁₈ aryl which may contain a side group, maycontain a bridge, may contain a heteroatom or may be substituted, orcombinations thereof; or a C₅-C₁₈ cycloalkyl which may contain a sidegroup, may contain a bridge, may contain a heteroatom or may besubstituted, or combinations thereof; or combinations thereof; R₂ is anR₁ group, a (C₁-C₁₀) alkyl-(C₃-C₁₀) cycloalkyl, which may be branched,may contain a heteroatom or may be substituted, or combinations thereof;or X and R₂ may form a ring; R₃ is an H or R₁; and Y is carbonyl oroxygen bound to a Schiff base, an oxine, a ketal, an acetal, anoxazolidine, a thiazolidine or an enol ester.
 4. A method foridentifying an antagonist of HM74 comprising, contacting a potentialantagonist with a cell expressing HM74 and determining whether in thepresence of said potential antagonist the signaling activity of HM74 isdecreased relative to the activity of HM74 in the presence of anagonist, wherein said potential antagonist has the structure:

where X is O, NR₂ or S; R₁ is a C₁-C₁₈ alkyl, which may be branched, maycontain a heteroatom or may be substituted, or combinations thereof; aC₁-C₁₈ alkenyl, which may be branched, may contain a heteroatom or maybe substituted, or combinations thereof; a C₁-C₁₈ alkynl, which may bebranched, may contain a heteroatom or may be substituted, orcombinations thereof; a C₃-C₁₈ aryl which may contain a side group, maycontain a bridge, may contain a heteroatom or may be substituted, orcombinations thereof; or a C₅-C₁₈ cycloalkyl which may contain a sidegroup, may contain a bridge, may contain a heteroatom or may besubstituted, or combinations thereof; or combinations thereof; R₂ is anR₁ group, a (C₁-C₁₀) alkyl-(C₃-C₁₀) cycloalkyl, which may be branched,may contain a heteroatom or may be substituted, or combinations thereof;or X and R₂ may form a ring; R₃ is H or R₁; and Y is carbonyl, a Schiffbase, an oxine, a ketal, an acetal, an oxazolidine, a thiazolidine or anenol ester.
 5. A method of modulating inflammation comprising exposing apatient in need of treatment an inflammation modulating amount of apharmaceutical composition comprising a compound of the formula:

where X is O, NR₂ or S; R₁ is a C₁-C₁₈ alkyl, which may be branched, maycontain a heteroatom or may be substituted, or combinations thereof; aC₁-C₁₈ alkenyl, which may be branched, may contain a heteroatom or maybe substituted, or combinations thereof; a C₁-C₁₈ alkynl, which may bebranched, may contain a heteroatom or may be substituted, orcombinations thereof; a C₃-C₁₈ aryl which may contain a side group, maycontain a bridge, may contain a heteroatom or may be substituted, orcombinations thereof; or a C₅-C₁₈ cycloalkyl which may contain a sidegroup, may contain a bridge, may contain a heteroatom or may besubstituted, or combinations thereof; or combinations thereof; R₂ is anR₁ group, a (C₁-C₁₀) alkyl-(C₃-C₁₀) cycloalkyl, which may be branched,may contain a heteroatom or may be substituted, or combinations thereof;or X and R₂ may form a ring; R₃ is H or R₁; and Y is carbonyl, a Schiffbase, an oxine, a ketal, an acetal, an oxazolidine, a thiazolidine or anenol ester.
 6. A compound of the formula:

where X is O, NR₂ or S; R₁ is a C₁-C₁₈ alkyl, which may be branched, maycontain a heteroatom or may be substituted, or combinations thereof; aC₁-C₁₈ alkenyl, which may be branched, may contain a heteroatom or maybe substituted, or combinations thereof; a C₁-C₁₈ alkynl, which may bebranched, may contain a heteroatom or may be substituted, orcombinations thereof; a C₃-C₁₈ aryl which may contain a side group, maycontain a bridge, may contain a heteroatom or may be substituted, orcombinations thereof; or a C₅-C₁₈ cycloalkyl which may contain a sidegroup, may contain a bridge, may contain a heteroatom or may besubstituted, or combinations thereof; or combinations thereof; R₂ is anR₁ group, a (C₁-C₁₀) alkyl-(C₃-C₁₀) cycloalkyl, which may be branched,may contain a heteroatom or may be substituted, or combinations thereof;or X and R₂ may form a ring; R₃is H or R₁; and Y is carbonyl, a Schiffbase, an oxine, a ketal, an acetal, an oxazolidine, a thiazolidine or anenol ester; with the proviso that when R₂ is methyl, ethyl orcyclohexyl, R₁ is not an n-alkyl or a C₁-C₄ branched alkyl; or when R₂is a C₁-C₄ alcohol or a C₁-C₄ branched alkyl which may be substitutedwith an acetyl group, R₁ is not an n-(C₁-C₈) alkyl, a (C₁-C₄) branchedalkyl or a thio substituted phenyl.